1. Field of the Invention
The present invention relates to a method for producing L-allysine acetal. More particularly, the present invention relates to a method of biochemical asymmetric hydrolysis of D,L-allysinamide acetal to produce corresponding L-allysine acetal. L-Allysine acetal is an important substance as an intermediate for producing medicines.
2. Description of the Related Art
Hitherto known methods for the production of L-allysine acetal include, for example, the method described in Japanese Patent Application Laid-open No. Hei 7-48259. This method comprises the steps of stereoselectively hydrolyzing N-acetyl-D,L-hydroxynorleucine, which has been derived by a two-step reaction from diethyl acetamidomalonate, with a swine liver acylase to obtain L-hydroxynorleucine, converting an amino group of the L-hydroxynorleucine to phthalimide, and a carboxyl group of the L-hydroxynorleucine to its methyl ester for protection, converting a hydroxyl group thereof to aldehyde by Swern oxidation, and further converting aldehyde thereof to dimethyl acetal, followed by deprotecting the phthalimide to obtain L-allysine dimethyl acetal as methyl ester. The method involves many steps, gives low yield, and requires expensive reagents, so that it cannot be said to be industrially advantageous.
Besides this, Bioorganic & Medicinal Chemistry, Vol.3, 1237-1240 (1995) describes a method for producing D,L-allysine ethylene acetal from 3,4-dihydro-2H-pyrane by 8-step reaction. This method also involves many steps, gives low yield, and requires further expensive reagents, so that it cannot be said to be industrially advantageous. The literature describes only the method for producing racemic modification but fails to describe optically active substance of L-allysine acetal.